Fix: Make "list" default command of imag-tag
Fix: Make "list" default command of imag-tag

The "list" command is advertised as default command for imag-tag. This
commit fixes the implementation so that the binary actually behaves this
way.

For this, the list() function gets a new parameter which tells it
whether there is a subcommand object to be expected in the Runtime.

Signed-off-by: Matthias Beyer <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@beyermatthias.de>

matthiasbeyer/imag,matthiasbeyer/imag